Polaron mobility and disordering of the sodium sublattice in triphylite-NaxFePO4

The interplay between sodium ordering and electron mobility in NaxFePO4 was investigated using a combination of synchrotron x-ray diffraction and Mössbauer spectrometry. Synchrotron x-ray diffraction measurements were carried out for a range of tempertures between 298K and 553 K. Rietveld analysis o...

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Bibliographic Details
Published in:Chemistry of materials 2016-05, Vol.28 (9)
Main Authors: Tracy, S. J., Mauger, L., Smith, H. L., Tan, H. J., Herriman, J. E., Xiao, Yuming, Fultz, B.
Format: Article
Language:English
Subjects:
Ions
Iron
MATERIALS SCIENCE
Physical and chemical processes
Sodium
Solutions
Online Access:Get full text
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Summary:The interplay between sodium ordering and electron mobility in NaxFePO4 was investigated using a combination of synchrotron x-ray diffraction and Mössbauer spectrometry. Synchrotron x-ray diffraction measurements were carried out for a range of tempertures between 298K and 553 K. Rietveld analysis of the diffraction patterns was used to determine the temperature of sodium redistribution on the lattice. This diffraction analysis also gives new information about the phase stability of the system. Mossbauer spectra were collected in the same temperature range. An analysis of the temperature evolution of the spectral shapes was used to identify the onset of fast electron hopping and determine the polaron hopping rate. Furthermore, the temperature evolution of the iron site occupancies from the Mossbauer measurements, combined with the synchrotron diffraction results shows a relationship between the onset of fast electron dynamics and the loss of local order on the sodium sublattice.
ISSN:0897-4756
1520-5002
DOI:10.1021/acs.chemmater.6b00226